Question

Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earth's crust, changing the measured strain across a fault zone and varying the electrical properties of underground rocks.

• A. changing the measured strain across a fault zone and varying
• B. changing measurements of the strain across a fault zone ,and varying
• C. changes in the measured strain across a, fault zone , and variations in
• D. changes in measurements of the strain across a fault zone , and variations among

Answer 1

The correct option is C

changes in the measured strain across a, fault zone , and variations in

Parallelism:
This sentence uses four phrases to describe the warning signs for all earthquake. These phrases should be parallel. The first sign is sudden fluctuations in local seismic activity, the second is tilting and other deformations of the Earth's crust. Tilting in this case is used as a noun just as deformations and fluctuations are nouns The first two signs are parallel. The third and fourth warning signs resemble tilling in the -ing form but they are not parallel because they are used as verbs rather than as nouns.
A: Changing and varying are used as verbs and so are not parallel to the nouns fluctuations and tilting.
B: The four signs are not parallel - the substitution of measurements of the strain distorts meaning.
C: Correct. In this sentence the four nouns - fluctuations, tilting, changes, variations - are parallel and the meaning of the measured strain is not distorted.
D: This sentence says that the measurements indicate an earthquake when the measured strain is the warning sign.

The correct answer is (c).